The present invention relates to an image sensing apparatus for performing image sensing by directing a lens and an image receiving element at a photographing subject.
A conventional camera, where the main unit of the camera is placed on a pan head which is rotatable in vertical and horizontal directions, the pan head is panned or tilted by manual operation or a motor or the like. In addition, a rotation-type image-sensing unit where a camera and a pan head are integrated, and which includes a driving unit for rotating the pan head, is available.
In such conventional apparatus consisting of a camera and a pan head, the pan head and the camera are separable. However, in a case of utilizing an electronic camera, codes from the camera such as signal wires and power-supplying wires and so on interferes with the camera operation, so that rotation angles of the camera in the vertical and horizontal directions are limited. In other words, the view angles (tilt/pan angles) in the vertical and horizontal directions are restricted. For instance, such camera cannot follow a subject moving around the camera and photograph a continuous image of the subject by rotating the camera. If other apparatuses, connected via wires to the electronic camera, are placed on the same pan head along with the camera, a continuous image of the subject can be sensed. However in this case, the entire mechanism including a motor and the like for rotating the pan head becomes large. Moreover, in such system, a user cannot monitor images, sensed by the camera, in real-time at a remote location.
Furthermore, in a case where the electronic camera is placed on the conventional pan head and focuses upon a subject located at a close distance, since the image-sensing surface of the camera is apart from a rotating axis of the camera, the image sensed by the camera, rotating on the rotating axis, is out of focus. For instance, assuming that a camera is focused upon an image as a subject which is placed in the lower portion of the image-sensing frame. If the camera is tilted downward to move the focused image to the upper portion of the image-sensing frame, the image becomes out of focus. More specifically, when the camera is rotated in the horizontal and vertical directions, the distance between the camera and the subject changes (the subject is not in the same spherical surface). Accordingly, the sensed image gives an odd impression to the user, thus it is difficult to see. At present, there is no image sensing apparatus available which can automatically follow a subject which arbitrarily moves in the vertical and horizontal directions and which can perform image sensing without giving odd impressions to the user.